Numerators of triangle related to enumeration of minimal 2-covers of a labeled n-set.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =3a(8) =10a(9) =1a(10) =1a(11) =2a(12) =865a(13) =71a(14) =1a(15) =1a(16) =5a(17) =2630a(18) =1427a(19) =181a(20) =1a(21) =1a(22) =3a(23) =163133a(24) =306553a(25) =36667a(26) =145a(27) =1a(28) =1a(29) =7